september 15, 2011 presented by: clay harris, pmp - city of austin federico mendoza, pe, ptoe –...
TRANSCRIPT
September 15, 2011
Presented by:
Clay Harris, PMP - City of Austin
Federico Mendoza, PE, PTOE – Brown & Gay Engineers, Inc.
Todd Lane Alternative Geometric Design StudyBen White to St. ElmoAustin, Texas
Project History
Todd Lane Alternative Geometric Design Study
Austin, Texas
Critical Goals and Concerns
• Enhance Vehicular and Pedestrian Safety
• Maintain acceptable Level of Service
• Improve Corridor Appearance
• Pursue Code Compliance
– Street, pedestrian, signage, etc.
• Stimulate Revitalization
• Maintain Commercial Activity during construction
Original Project Design
• Alternative 1
– 4-lane divided on Todd Lane
– 4-lane divided boulevard on
Pleasant Valley Road
– Standard signalized intersection
at Todd Lane and St. Elmo Road
Todd Lane Alternative Geometric Design Study
Austin, Texas
Alternate Design
• Alternative 2A
– 3-lane roadway section on Todd
Lane
– 4-lane divided on Pleasant Valley
Road; Single-lane NB approach
– Single-lane Roundabout at Todd
Lane and St. Elmo Road
– Fits within existing ROW
Todd Lane Alternative Geometric Design Study
Austin, Texas
Todd Lane Alternative Geometric Design Study
Austin, Texas
Roundabout Benefits
• Improved pedestrian and vehicular safety
• Elimination of left-turn, head-on, and T-bone collisions
• Vehicle-vehicle conflicts decreases from 32 to 8
• Crash reduction:
– 90% fatal crashes, 76% injury crashes, 35% overall
• Yield operation promotes minimal queuing
• Significant reduction in delay
• Opportunity for community landmark
Todd Lane Alternative Geometric Design Study
Austin, Texas
Study Scope
• Traffic Volumes
• Single-Lane Roundabout Concept Layout
• Two-Lane Roundabout Concept Layout
• Truck Vehicle Paths
• Traffic Simulation Analysis
• Conclusions
Traffic Volumes
• Existing Peak Hour Volumes – Todd Lane at St. Elmo Rd.
– AM Peak: Heavier Volumes
– PM Peak: Relatively Balanced Flows
Todd Lane Alternative Geometric Design Study
Austin, Texas
ApproachAM Peak Hour(Vehicles per
hour)
PM Peak Hour(Vehicles per
hour)
Northbound - -
Southbound 301 474
Eastbound 458 523
Westbound 677 327
Total 1,436 1,324
Traffic Projections
• Derived from Existing Counts and CAMPO Estimates
• Daily Traffic Volume Forecasts – Todd Lane at St. Elmo
Road
Todd Lane Alternative Geometric Design Study
Austin, Texas
Intersection Leg
2015Daily Volumes(Vehicles per
day)
2025Daily Volumes(Vehicles per
day)
2035Daily Volumes(Vehicles per
day)
North 11,100 14,000 18,000
South 11,400 15,400 15,500
East 3,370 5,518 7,000
West 9,100 8,500 7,900
Todd Lane Alternative Geometric Design Study
Austin, Texas
Single-Lane Roundabout Concept
Todd Lane Alternative Geometric Design Study
Austin, Texas
WB-50 Design Vehicle
Todd Lane Alternative Geometric Design Study
Austin, Texas
WB-50 Design Vehicle
Traffic Simulation Results – Year 2025
Todd Lane Alternative Geometric Design Study
Austin, Texas
Peak Hour Period Approach
Intersection Delay
Alternative 1 Alternative 2A
Standard Intersection
Single Lane Roundabout
AM PEAK
Northbound 50.9 10.4
Southbound 17.3 8.0
Eastbound 63.1 4.4
Westbound 90.6 62.8
ALL 53.8 20.1
PM PEAK
Northbound 37.0 4.9
Southbound 38.4 9.8
Eastbound 29.2 17.5
Westbound 31.9 6.5
ALL 34.9 10.0
Traffic Simulation Results – Year 2035
Todd Lane Alternative Geometric Design Study
Austin, Texas
Peak Hour Period Approach
Intersection Delay
Alternative 1 Alternative 2B
Standard Intersection
Two Lane Roundabout
AM PEAK
Northbound 57.3 38.8
Southbound 21.0 6.1
Eastbound 75.4 22.0
Westbound 105.1 112.6
ALL 63.0 52.6
PM PEAK
Northbound 41.0 7.2
Southbound 41.9 7.0
Eastbound 33.9 10.4
Westbound 52.4 7.0
ALL 40.9 8.4
Vissim Micro-simulation: 2025 AM Peak
Todd Lane Alternative Geometric Design Study
Austin, Texas
2025 AM Peak – Signal vs. Roundabout
Todd Lane Alternative Geometric Design Study
Austin, Texas
Project Schedule
• Alternate Design– Complete Real Estate Acquisition - Fall 2011– Begin Design Fall 2011– Complete Design Fall 2012– Begin construction – Spring 2013
Conclusions
• The single-lane roundabout will provide:
– Acceptable level of service through year 2025 during peak hours
– Least amount of delay to motorists during off-peak hours
– Higher level of safety (reduction in crashes) for vehicles
– Higher level of safety for pedestrians and bicyclists
– A safe and efficient alternative to a standard signal that will fit within the
R.O.W. footprint
Todd Lane Alternative Geometric Design Study
Austin, Texas
Questions? Comments?
• Clay Harris, Project Manager Public Works Department
• Call 512-974-7895
• Email [email protected]
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